System and method for allocating resources in a non-transparent multi-hop relay network

ABSTRACT

A method for allocating resources in a wireless network includes establishing one or more links. The method also includes the following iterative steps: allocating a first number of slots to the relay links; dividing the first number of slots among the relay links; determining a representative relay data rate indicative of a data rate provided by one of the relay links for one of the multi-hop access links; allocating the second number of slots to the multi-hop access links; dividing the second number of slots among the multi-hop access links; determining the effective multi-hop data rate based on the minimum of the representative relay link data rate and the multi-hop data rate; allocating the third number of slots to the single-hop access links; dividing the third number of slots among the single-hop access links; and upon the single-hop data rate being approximately equal to the effective multi-hop data rate, provisioning the first, second and third number of slots.

TECHNICAL FIELD OF THE INVENTION

This invention relates in general to communication systems and, moreparticularly, to an apparatus and method for allocating resources in anon-transparent multi-hop relay network.

BACKGROUND OF THE INVENTION

While broadband network services and Voice over IP (VoIP) productscontinue to grow and expand, so does the demand for wireless networkfunctionality. To help meet this demand, networks are being developedthat use multiple base stations, relay stations, access points or otherpoints of contact. In many scenarios the various base stations, relaystations, access points or other points of contact communicate with oneanother via wireless channels. One emerging wireless technology is IEEE802.16, popularly known as WiMAX. WiMAX provides broadband wirelessaccess, with a single base station providing coverage over a large area(theoretically up to 31 miles). The coverage area of a cell (the areacontrolled by a particular base station) may be enhanced through the useof relay stations. Other wireless networking technologies include ThirdGeneration (3G), Third Generation Partnership Project (3GPP), and IEEE802.11, popularly known as WiFi.

SUMMARY

In accordance with a particular embodiment, a method for allocatingresources in a wireless network includes establishing one or more relaylinks, one or more single-hop access links, and one or more multi-hopaccess links. The method also includes iterative steps that are repeateduntil a first, second and third number of slots are provisioned. Theiterative steps include allocating the first number of slots to therelay links and dividing them among the relay links. The iterative stepsalso include determining a representative relay data rate indicative ofa data rate provided by one of the relay links for a respective one ofthe multi-hop access links. The representative relay data rate is basedon the number of slots divided to the respective relay link and thenumber of multi-hop access links established with the respective relaystation. The iterative steps further include allocating the secondnumber of slots to the multi-hop access links and dividing them amongthe multi-hop access links ensuring that each multi-hop access linkcomprises an approximately equal multi-hop data rate. The iterativesteps also include determining the effective multi-hop data rate basedon the minimum of the representative relay link data rate and themulti-hop data rate. The iterative steps further include allocating thethird number of slots to the single-hop access links and dividing thethird number of slots among the single-hop access links ensuring thateach single-hop access link comprises an approximately equal single-hopdata rate. The iterative steps also include determining a minimum datarate based on the minimum of the single-hop data rate and the effectivemulti-hop data rate. Upon determining that the minimum data rate hasreached its maximum value, the iterative steps additionally includeprovisioning the first number of slots to the relay links, the secondnumber of slots to the multi-hop access links, and the third number ofslots to the single-hop access links.

Technical advantages of particular embodiments may include a moreefficient utilization of wireless resources in a multi-hop relaynetwork. Accordingly, a multi-hop relay network may be able toaccommodate a greater number of endpoints or provide the same number ofendpoints with greater resources as compared to traditional multi-hoprelay networks.

Other technical advantages will be readily apparent to one skilled inthe art from the following figures, descriptions and claims. Moreover,while specific advantages have been enumerated above, variousembodiments may include all, some or none of the enumerated advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of particular embodiments and theiradvantages, reference is now made to the following description, taken inconjunction with the accompanying drawings, in which:

FIG. 1 illustrates a communication system comprising variouscommunication networks, in accordance with a particular embodiment;

FIG. 2 illustrates a wireless network comprising a more detailed view ofa base station and several relay stations, in accordance with aparticular embodiment;

FIGS. 3A and 3B illustrate block diagrams of the frame structure of abase station frame and a relay station frame, respectively, for use witha non-transparent relay station, in accordance with particularembodiments;

FIG. 4 illustrates a method for allocating resources in anon-transparent multi-hop relay network, in accordance with particularembodiments.

DETAILED DESCRIPTION

FIG. 1 illustrates a communication system comprising variouscommunication networks, in accordance with a particular embodiment.Communication system 100 may be comprised of multiple networks 110. Eachnetwork 110 may be any of a variety of communication networks designedto facilitate one or more different services either independently or inconjunction with other networks. For example, networks 110 mayfacilitate internet access, online gaming, file sharing, peer-to-peerfile sharing (P2P), voice over internet protocol (VoIP) calls, videoover IP calls, or any other type of functionality typically provided bya network. Networks 110 may provide their respective services using anyof a variety of protocols for either wired or wireless communication.For example, network 110 a may comprise an 802.16 wireless network,popularly known as WiMAX, which may include base stations (e.g., basestation 120) and relay stations (e.g., relay stations 130). Network 110a may provide for the use of relay stations 130 by implementing 802.16j.A WiMAX network that uses relay stations may be referred to as a mobilemulti-hop relay (MMR) network.

In particular embodiments, one or more endpoints may have established awireless connection with a relay station (access link). Accordingly, therelay station may need to ensure that there are sufficient wirelessresources available for a wireless connection (relay link) betweenitself and a base station to maintain each of the wireless connectionswith the endpoints. For example, if endpoints 140 a and 140 b are bothconnected to relay station 130 a then it may be desirable for wirelessconnection 150 d to comprise sufficient resources to support bothwireless connections 150 a and 150 b evenly (e.g., both endpoints 140 aand 140 b have the same data rate). This may be referred to as a ratefair setup (where all the endpoints serviced by a particular basestation, either directly or indirectly, receive a similar data rate).While the endpoints may be receiving a similar data rate they may beconsuming different quantities of wireless resources based on theefficiency and/or protocol that the endpoint uses. Thus, the wirelessresources used by wireless connection 150 d may correspond to the totalamount of wireless resources used for endpoints 140 a and 140 b. This inturn impacts the amount of resources available to base station 120 forcommunicating with endpoints connected directly thereto (e.g., endpoint140 c). In some embodiments, the amount of wireless resources availableto a particular component may be measured by the number of slots withina communication frame as discussed in more detail below. Particularembodiments may take into account the balance of wireless resourcesbetween relay links and access links when determining how wirelessresources should be distributed.

Between each relay station and/or base station there may be a wirelessconnection, such as wireless connection 150 d. As mentioned above, thiswireless connection may be referred to as a relay link. A wirelessconnection may comprise various wireless resources such as, for example,a combination of a particular center frequency, a particular bandwidth,a particular time slot, and/or a particular subchannel (for example, asdescribed in a downlink or uplink MAP). In particular embodiments, itmay be convenient to discuss the amount of resources in terms of slots.Depending on the embodiment, a slot may comprise a particular number ofsubchannels and symbols (also known as time slots). For example, Section8.4.3.1 in the Institute of Electrical & Electronics Engineers (IEEE)802.16e-2005 Standard specifies a slot comprising a single subchanneland two symbols. An increase in the number of wireless connections 150may increase the impact and severity of interference between wirelessconnections 150. In particular embodiments, uplink sounding may be usedto estimate the channel gain and interference strength between multiplerelay stations 130 and base station 150. The uplink sounding may,therefore, be used in determining the quality and/or efficiency of thevarious wireless connections.

Although communication system 100 includes four different types ofnetworks, networks 110 a-110 d, the term “network” should be interpretedas generally defining any network or combination of networks capable oftransmitting signals, data, and/or messages, including signals, data ormessages transmitted through WebPages, e-mail, text chat, voice over IP(VoIP), and instant messaging. Depending on the scope, size and/orconfiguration of the network, any one of networks 110 a-110 d may beimplemented as a LAN, WAN, MAN, PSTN, WiMAX network, global distributednetwork such as the Internet, Intranet, Extranet, or any other form ofwireless or wired networking.

Generally, networks 110 a, 110 c, and 110 d provide for thecommunication of packets, cells, frames, or other portions ofinformation (generally referred to as packets herein) between endpoints140 and/or nodes 170. Networks 110 may include any number andcombination of wired links 160, wireless connections 150, nodes 170and/or endpoints 140. For purposes of illustration and simplicity,network 110 a is a MAN that may be implemented, at least in part, viaWiMAX, network 110 b is a PSTN, network 110 c is a LAN, and network 110d is a WAN.

In particular embodiments, networks 110 a, 110 c and 110 d may be IPnetworks. IP networks transmit data by placing the data in packets andsending each packet individually to the selected destination, along oneor more communication paths. Network 110 b may, for example, be a PSTNthat may include switching stations, central offices, mobile telephoneswitching offices, pager switching offices, remote terminals, and otherrelated telecommunications equipment that are located throughout theworld. Network 110 d may be coupled to network 110 b through a gateway.Depending on the embodiment, the gateway may be a part of network 110 bor 110 d (e.g., nodes 170 e or 170 c may comprise a gateway). Thegateway may allow PSTN 110 d to be able to communicate with non-PSTNnetworks such as networks 110 a, 110 c and 110 d.

Any of networks 110 a, 110 c or 110 d may be coupled to other IPnetworks including, but not limited to, the Internet. Because IPnetworks share a common method of transmitting data, signals may betransmitted between devices located on different, but interconnected, IPnetworks. In addition to being coupled to other IP networks, any ofnetworks 110 a, 110 c or 110 d may also be coupled to non-IP networksthrough the use of interfaces or components such as gateways.

Networks 110 may be connected to each other and with other networks viaa plurality of wired links 160, wireless connections 150, and nodes 170.Not only do the wired links 160, wireless connections 150, and nodes 170connect various networks but they also interconnect endpoints 140 withone another and with any other components coupled to or a part of any ofnetworks 110. The interconnection of networks 110 a-110 d may enableendpoints 140 to communicate data and control signaling between eachother as well as allowing any intermediary components or devices tocommunicate data and control signals. Accordingly, users of endpoints140, may be able to send and receive data and control signals betweenand among each network component coupled to one or more of networks 110a-110 d.

As noted above, wireless connections 150 may represent a wireless linkbetween two components using, for example, WiMAX. The extended range ofa WIMAX base station and/or relay station may allow network 110 a tocover the larger geographic area associated with a MAN while using arelatively small number of wired links. More specifically, by properlyarranging base station 120 and multiple relay stations 130 around ametropolitan area, the multiple relay stations 130 may use wirelessconnections 150 to communicate with base station 120 and wirelessendpoints 140 throughout the metropolitan area. Then base station 120may, through wired connection 160 a, communicate with other basestations, network components not capable of establishing a wirelessconnection, and/or other networks outside of the MAN, such as network110 d or the Internet.

Nodes 170 may include any combination of network components, sessionborder controllers, gatekeepers, base stations, conference bridges,routers, hubs, switches, gateways, endpoints, or any other hardware,software, or embedded logic implementing any number of communicationprotocols that allow for the exchange of packets in communication system100. For example, node 170 a may comprise another base station that iswired to base station 120 via link 160 j and to network 110 d via link160 a. As a base station, node 170 a may be able to establish severalwireless connections with various other base stations, relay stations,and/or endpoints. As another example, node 170 e may comprise a gateway.This may allow network 110 b, a PSTN network, to be able to transmit andreceive communications from other non-PSTN networks, such as network 110d, an IP network. Node 170 e, as a gateway, works to translatecommunications between the various protocols used by different networks.

Endpoints 140 and/or nodes 170 may provide data or network services to auser through any combination of hardware, software embedded in acomputer readable medium, and/or encoded logic incorporated in hardwareor otherwise stored (e.g., firmware). For example, endpoints 140 a-140 dmay include an IP telephone, a computer, a video monitor, a camera, apersonal data assistant, a cell phone or any other hardware, softwareand/or encoded logic that supports the communication of packets (orframes) using networks 110. Endpoints 140 may also include unattended orautomated systems, gateways, other intermediate components or otherdevices that can send or receive data and/or signals. Although FIG. 1illustrates a particular number and configuration of endpoints,connections, links, and nodes, communication system 100 contemplates anynumber or arrangement of such components for communicating data. Inaddition, elements of communication system 100 may include componentscentrally located (local) with respect to one another or distributedthroughout communication system 100.

FIG. 2 illustrates a wireless network comprising a more detailed view ofbase station 210 and relay stations 250, in accordance with a particularembodiment. In different embodiments the network may comprise any numberof wired or wireless networks, base stations, endpoints, relay stations,and/or any other components that may facilitate or participate in thecommunication of data and/or signals whether via wired or wirelessconnections. For simplicity, wireless network 200 of the depictedembodiment comprises wired network 205, base station 210, endpoints 270and relay stations 250. Base station 210 comprises processor 212, memory214, interface 216, radio 217 and antenna 218. Similarly, relay stations250 comprise processors 252, memory modules 254, radios 257 and antennas258. These components may work together in order to provide base stationand/or relay station functionality, such as providing wirelessconnections in a wireless network (e.g., a WiMAX wireless network).Network 205 may comprise one or more of the networks described abovewith respect to FIG. 1. For example, network 205 may comprise theInternet, a LAN, WAN, MAN, PSTN or some combination of the above.

Processor 212 may be a microprocessor, controller, or any other suitablecomputing device, resource, or combination of hardware, software and/orencoded logic operable to provide, either alone or in conjunction withother base station 210 components, such as memory 214, base station 210functionality. Such functionality may include providing various wirelessfeatures discussed herein to an endpoint or relay station, such asendpoint 270 h or relay station 250 a. For example, processor 212 maydetermine how to distribute wireless resources among the access linksand relay links used by endpoints 270 and relay stations 250. Thedistribution of wireless resources may be such that a rate fair schememay be implemented. In determining the distribution of wirelessresources, processor 212 may take into account the number of relay linksand access links that are needed as well as the efficiency with whichthose links are able to transmit/receive data. Furthermore, as thenumber and type of endpoints change, processor 212 may be able to adjustthe allocation of wireless resources on a frame-by-frame basis.

Memory 214 may be any form of volatile or non-volatile memory including,without limitation, magnetic media, optical media, random access memory(RAM), read-only memory (ROM), flash memory, removable media, or anyother suitable local or remote memory component or components. Memory214 may store any suitable data or information utilized by base station210, including software embedded in a computer readable medium, and/orencoded logic incorporated in hardware or otherwise stored (e.g.,firmware). In some embodiments memory 214 may store information used byprocessor 212 in determining how to divide wireless resources betweenaccess links and relay links. Memory 214 may also store the resultsand/or intermediate results of the various calculations anddeterminations performed by processor 212. Memory 214 may also storeinformation regarding the quality of particular links. This quality maybe an indication of how efficient a particular link is at transferringdata. Memory 214 may also maintain a list, database, or otherorganization of data useful for determining how to route data to theproper endpoints and/or relay stations. For example, in some embodimentsa tree structure (as opposed to a mesh structure) may be used in routingdata from an endpoint to a base station. More specifically, there may bea known path from base station 210 to endpoint 270 b. This path, or aportion thereof, may be stored in memory 214.

Base station 210 also comprises interface 216 which may be used for thewired communication of signaling and/or data between base station 210and network 205. For example, interface 216 may perform any formattingor translating that may be needed to allow base station 210 to send andreceive data from network 205 over a wired connection. Interface 216 mayalso be used to establish any wired connections between base station 210and other networks or network components.

Radio 217 may be coupled to or a part of antenna 218. Radio 217 mayreceive digital data that is to be sent out to other base stations,relay stations and/or endpoints via a wireless connection. The wirelessconnection may use the wireless resources assigned to base station 210.The wireless resource may include, for example, a combination of one ormore of a center frequency, bandwidth, time slot, channel, and/orsubchannel. In particular embodiments this information may be stored inmemory module 214. Radio 217 may convert the digital data into a radiosignal having the appropriate center frequency and bandwidth parameters.These parameters may have been determined ahead of time by somecombination of processor 212 and memory 214. The radio signal may thenbe transmitted via antenna 218 for receipt by any appropriate componentor device (e.g., relay station 250 d). Similarly, radio 217 may convertradio signals received from antenna 218 into digital data to beprocessed by processor 212.

Antenna 218 may be any type of antenna capable of transmitting andreceiving data and/or signals wirelessly. In some embodiments, antenna218 may comprise one or more omni-directional, sector or panel antennasoperable to transmit/receive radio signals between 2 GHz and 66 GHz. Anomni-directional antenna may be used to transmit/receive radio signalsin any direction, a sector antenna may be used to transmit/receive radiosignals from devices within a particular area, and a panel antenna maybe a line of sight antenna used to transmit/receive radio signals in arelatively straight line. Together, radio 217 and antenna 218 may form awireless interface. This wireless interface may be used to establishconnections with various wireless components, including endpoints andrelay stations.

Relay stations 250 may, in essence, be smart repeaters between basestation 210 and endpoints 270. Depending on the embodiment andconfiguration of a relay station, one or more of relay stations 250 maybe transparent or non-transparent. From the perspective of an endpoint,a transparent relay station is perceived as though the endpoint werecommunicating with base station 210 while a non-transparent relaystation is perceived as though it were another base station. Morespecifically, a transparent relay station may not transmit relatedcontrol information (e.g. a preamble or downlink/uplink MAP) whereas anon-transparent relay station may transmit this information.

Relay stations 250 may comprise components similar to those of basestation 210. One exception for relay stations 250 is that relay stations250 may not include an interface for a wired connection. This may bebecause relay stations 250 may communicate with base station 210 andother relay stations 250 via wireless connections. Thus, relay stations250 may not need a wired connection. By allowing relay stations 250 tobe deployed without a wired connection, the initial deployment cost maybe lower because network wires do not have to be run out to each relaystation 250. In particular embodiments, a relay station may include aninterface for a wired connection. Relay stations 250 a, 250 b, 250 c,and 250 d may comprise similar components that may provide similarfunctionality. Therefore, for simplicity, the following discussion ofthe relay station components depicted in FIG. 2 may refer to thecomponent in general and may be applied to each relay station.

Like base station 210, relay station 250 comprises a processor.Processor 252 may be a microprocessor, controller, or any other suitablecomputing device, resource, or combination of hardware, software and/orencoded logic operable to provide, either alone or in combination withother relay station 250 components, such as memory module 254, relaystation 250 functionality. Such functionality may include providingvarious wireless features discussed herein to an endpoint or basestation, such as endpoints 270 a-270 b or base station 210. Inparticular embodiments, processor 252 may determine the quality of oneor more wireless connections or links. This information may be providedto base station 218.

Like memory 214, memory module 254 may be any form of volatile ornon-volatile memory including, without limitation, magnetic media,optical media, random access memory (RAM), read-only memory (ROM), flashmemory, removable media, or any other suitable local or remote memorycomponent or components. Memory module 254 may store any suitable dataor information, including software embedded in a computer readablemedium, and/or encoded logic incorporated in hardware or otherwisestored (e.g., firmware) utilized by relay station 250. In someembodiments, memory module 254 may store information indicative of thesize, features and number of slots that may be needed or used for eachwireless connection. Memory module 254 may additionally maintain a list,database, or other organization of data useful for determining how toroute data to the proper endpoints, base stations and/or relay stations.

Radio 257 may be coupled to or a part of antenna 258. Radio 257 mayreceive digital data from, for example, processor 252 that is to be sentout to other base stations, relay stations and/or endpoints via awireless connection. The wireless connection may use the wirelessresources assigned to relay station 250. The wireless resource mayinclude, for example, a combination of one or more of a centerfrequency, bandwidth, time slot, channel, and/or subchannel. Inparticular embodiments this information may be stored in memory module254. Radio 257 may convert the digital data into a radio signal havingthe appropriate center frequency and bandwidth parameters. Theseparameters may have been determined ahead of time by base station 210 orprocessor 252. The radio signal from radio 257 may then be transmittedvia antenna 258 to the appropriate recipient (e.g., base station 210) atthe appropriate time. Radio 257 may also convert radio signals receivedby antenna 258 into digital data to be processed by processor 252.

Antenna 258 may be any type of antenna capable of transmitting andreceiving data and/or signals wirelessly. In some embodiments, antenna258 may comprise one or more omni-directional, sector or panel antennasoperable to transmit/receive radio signals between 2 GHz and 66 GHz.Antenna 258 and radio 257 may collectively be referred to as a wirelessinterface, or simply an interface. This wireless interface may be usedto establish connections with various wireless components, includingendpoints and base stations.

Endpoints 270 may be any type of wireless endpoints able to send andreceive data and/or signals to and from base station 210 or relaystations 250. Some possible types of endpoints 270 may include desktopcomputers, PDAs, cell phones, laptops, and/or VoIP phones.

In particular embodiments, wireless network 200 may be provisioned sothat each endpoint 270 receives the same data rate. This may be referredto as rate fair. While each endpoint 270 may receive approximately thesame data rate, the amount of resources that may be used may vary. Forexample, a particular endpoint that is using a less efficient wirelesscommunication protocol or is in an area with poor signal strength mayconsume more wireless resources to achieve the same data rate as a moreefficient endpoint. Furthermore, as may be apparent, in order tomaintain the data rates for the access links (e.g., between endpoints270 a and 270 b and relay station 250 d), the relay link (e.g., betweenrelay station 250 d and base station 210) needs to support matching datarates. The more wireless resources (e.g., slots) used by base station210 for relay links, the fewer wireless resources it will have availablefor its own access links (e.g., between endpoint 270 h and base station210).

Processor 212, for example, may take these competing factors intoaccount when determining the data rate for endpoints 270 and how toallocate wireless resources. This may best be seen by the followingexample in which relay stations 250 are non-transparent relays stations.In this example it may be assumed that data is communicated using framesas depicted in FIGS. 3A-3B and discussed below.

FIGS. 3A and 3B illustrate block diagrams of the frame structure of abase station frame and a relay station frame, respectively, for use witha non-transparent relay station, in accordance with particularembodiments. Frames 300 comprise a fixed number of slots (a slot maycomprise a specific time, duration and channel/subchannel). The actualnumber of slots may depend on the size of a slot and the size of frame300 specified by the protocol used by network 200. In particularembodiments, frames 300 may comprise four-hundred fifty slots. Frames300 may be broken down into two different sub-frames, downlink sub-frame310 and uplink sub-frame 320. The sub-frames may further be broken downinto different zones. Downlink sub-frame 310 may comprise a downlinkaccess zone 311 and a downlink relay zone 312. In addition, frame 300 bmay also include transition 313 b which may provide time for the relaystation to transition from transmitting to receiving. Uplink sub-frame320 may comprise uplink access zone 321 and uplink relay zone 322. Thesize of these zones may be based on the number of slots used by aparticular set of links. For example, the size of relay zone 312 may bebased on the number of slots assigned to relay links 280 of FIG. 2. Thuswhile a frame may be of a fixed size (e.g., duration and channel), thezones within a frame may vary based on the number of slots assigned to,for example, the relay links between a base station and any relaystations.

Within downlink sub-frame 310, downlink access zone 311 a may be used bya base station (e.g., base station 210) to transmit data to anyendpoints (e.g., endpoint 270 h) connected thereto. Similarly, downlinkaccess zone 311 b may be used by the relay stations (e.g., relaystations 250) to transmit data to any of the endpoints (e.g., endpoints270 a-270 g) connected thereto. Because the relay stations arenon-transparent they may be able to transmit data to their endpoints atthe same time that the base station is transmitting data to itsendpoints. In particular embodiments, both downlink access zones 311 mayinclude control information, such as a preamble, and downlink and uplinkMAPs. Downlink relay zone 312 a may be used by the base station totransmit data to the relay stations connected thereto. Accordingly, therelay stations may use downlink relay zone 312 b to receive data fromthe base station.

Within uplink sub-frame 320, uplink access zone 321 a may be used by thebase station to receive data from any endpoints connected thereto.Similarly, the relay stations may use uplink access zone 321 b toreceive data from any of the endpoints connected thereto. Uplink relayzone 322 a may then be used by the base station to receive data from anyrelay stations connected thereto. Accordingly uplink relay zone 322 bmay be used by the relay stations to transmit data to the base station.

Returning to FIG. 2, it may be assumed, for purposes of this example,that wireless network 200 includes non-transparent relay stations 250.In order to determine the data rate each endpoint 270 is to receive, andthus what size each zone of the frame needs to be, processor 212 mayfirst need to receive certain information. This information may includethe number of relay stations and endpoints that are connected, bothdirectly and indirectly (e.g., through one of relay stations 250) tobase station 210 as well as the quality of each link between eachcomponent. All, some, or none of this information may automatically beprovided to base station 210 as part of the wireless protocol used bywireless network 200. The link quality information may be used todetermine the efficiency with which data is communicated over aparticular link. In some embodiments processor 252 c of relay station250 c, for example, may aggregate and/or average the link quality of allits access links (e.g., the links used by endpoints 270 c and 270 d).Base station 210 may receive this information via antennae 218 and radio217 and store it in memory 214.

Processor 212 may then tentatively allocate a certain number of slots tobe used for relay links 280. Using the link quality informationassociated with the respective relay links, stored in memory 214, andthe number of endpoints connected to each relay station. Morespecifically, the number of slots assigned to a particular relay stationmay be proportional to the number of endpoints connected thereto andinversely proportional to the link quality of its relay link. Then slotsmay be divided among access links 290 a-290 g for endpoints 270 a-270 gconnected to relay stations 250 such that each of endpoints 270 a-270 greceive an approximately equal data rate. Depending on the number ofslots assigned to the relay link and access link, and their respectivelink quality, the respective relay link and access link may provide anendpoint with different data rates. Accordingly, the effective data ratefor a particular endpoint, (e.g., endpoint 270 b), is the minimum of thedata rate provided by its access link (e.g., access link 290 b) and itsrespective portion of its relay link (e.g., relay link 280 d). Inparticular embodiments, the number of slots processor 212 may assign toendpoints connected directly to base station 210 may be based on thenumber of slots that have been assigned to the relay links. Morespecifically, processor 212 may subtract the number of slots used indownlink relay zone 312 and uplink relay zone 322 from the total numberof slots available for frame 300. In other words as the size of relayzones 312 and 322 increases the size of access zones 311 and 320decreases.

Processor 212 then has enough information to determine whether all theaccess links 290 are providing their respective endpoints 270 with asimilar data rate. More specifically, processor 212 may be able tocompare the data rate of endpoint 270 h with the effective data rate forany of endpoints 270 a-270 g. If the data rates are not similar,processor 212 may adjust the number of slots that were previouslyassigned for use by relay links 280 and repeat the above describeddeterminations. For example, in particular embodiments processor 212 mayincrease or decrease the number of slots that were tentatively assignedto be used for relay links 280 in 5 slot increments. Then it may repeatthe above determinations and calculations so as to compare the resultingdata rate of access links 290. This may be repeated until processor 212has determined that each endpoint 270 will receive a similar data rate.

In particular embodiments, one or more of relay stations 250 maycommunicate with base station 210 via another relay station 250. Inother words, it may be that two or more relay stations are cascaded suchthat a communication from an endpoint connected to a relay station atthe end of the cascade may pass through, and be relayed by, anotherrelay station before it reaches base station 210. Besides relayingcommunication from another relay station, the intermediary relay stationmay also have endpoints connected thereto. Thus, as may be apparent, therelay link for the intermediary relay station may need sufficientbandwidth to cover the endpoint connected thereto, as well as theendpoints connected to the relay station at the end of the cascade. Anarrangement of cascaded relay stations may easily be envisioned if itwere assumed that relay link 280 b went from relay station 250 b torelay station 250 c (instead of to base station 210). Particularembodiments may account for the cascading relay stations by each of therelay stations (beginning with the relay station furthest from the basestation) adjusting the zone size assigned to itself and the frame sizeassigned to its children relay stations from next hop to the end of thecascade so that every endpoint connected to any of these relay stationsgets equal throughput on the relay link.

FIG. 4 illustrates a method for allocating resources in anon-transparent multi-hop relay network, in accordance with particularembodiments. The method begins at step 405 with the establishment oflinks. This may include establishing one or more relay links between thebase station and one or more relay stations, one or more single-hopaccess links between the base station and one or more endpoints, and oneor more multi-hop access links between the relay stations and one ormore endpoints (different than the endpoints linked to the basestation). For convenience, the endpoints linked to the base station maybe referred to as single-hop endpoints and the endpoints linked to therelay stations may be referred to as multi-hop endpoints.

At step 410 link quality information is collected. The link qualityinformation may be collected for any of the single-hop access links,multi-hop access links and/or relay links. The link quality informationreceived at step 410 may be indicative of the efficiency with which alink may be able to communicate data. This efficiency may be affected bysuch factors as the distance between the endpoint and the relay stationor base station, the signal strength, and/or the protocol being used. Insome embodiments, the link quality of a particular set of links, such asa set of multi-hop access links between a set of endpoints and a relaystation, may be aggregated, averaged, or otherwise summarized. The linkquality information may be determined during establishment of the links(step 405), on a periodic basis, or after a certain number of frames.Thus, the base station may maintain a relatively current record of thelink quality for various access links and relay links.

At step 415 a first number of slots are allocated to the relay links.The first number of slots assigned to the relay links may be based onthe number of slots that were previously assigned. More specifically, ininstances where step 415 is being executed for the first time for aparticular frame, the first number of slots may be based on the numberof slots that were assigned to the relay links in a previous frame. Ininstances where step 415 is being executed for the second time for thesame frame, the first number of slots may be based on the number ofslots that were initially assigned at step 415 during a previousiteration along with information related to the disparity between thesingle-hop data rate and the effective multi-hop data rate. In somescenarios, such as the very first time step 415 is executed, theassignment of the first number of slots may be predetermined.

At step 420, the first number of slots are divided among the relaylinks. The first number of slots may be divided so as to take intoaccount current operating conditions. More specifically, the number ofslots assigned to a particular relay station may be proportional to thenumber of endpoints connected thereto and inversely proportional to thelink quality of its relay link. Thus, the first number of slots may bedivided so that those relay stations needing more resources will beassigned more slots. More specifically, because this method isattempting to implement a rate fair scheme, it may be assumed that allthe endpoints are to receive the same data rate. Thus, as the number ofendpoints increase, so does the data rate requirement of the relay link.Additionally, lower quality links, being less efficient in transferringdata, may need additional slots to achieve the same data rate as moreefficient links.

At step 425 a representative relay data rate is determined. Therepresentative relay data rate is based on the data rate of therespective relay link and the number of multi-hop access linksestablished with the respective relay station. In other words, therepresentative relay data rate is the data rate the relay link is ableto provide to an individual multi-hop access link. In particularembodiments, the relay data rate may be based on the number of slotsthat were divided to the respective relay link at step 420 and the linkquality of the relay link as collected at step 410.

At step 430, a second number of slots are allocated to the multi-hopaccess links. The second number of slots assigned to the multi-hopaccess link may be determined in part by the first number of slots thatwere assigned to the respective relay link. More specifically, thenumber of slots available for the multi-hop access links may bedetermined from the total number of slots that are available (within adownlink or uplink sub-frame) less the first number of slots that wereassigned to the relay link (e.g., as depicted in FIG. 3B). In particularembodiments, the number of slots that are available for the multi-hopaccess links may vary between relay stations. The multi-hop access linksserviced by a particular relay station may be a subset of the secondnumber of access links serviced by a particular base station. Morespecifically, a base station may service multi-hop access links frommultiple different relay stations.

At step 435 the second number of slots are divided among the multi-hopaccess links. By taking into account the respective link quality of eachaccess link, it may be possible to ensure that each multi-hop endpointis provided with an approximately equal data rate. In particularembodiments, each relay station may divide the slots among the endpointsconnected thereto.

At step 440, the effective multi-hop data rate is determined. In someembodiments, the effective multi-hop data rate may be the lesser of therepresentative relay link data rate and the multi-hop data rate. Asalluded to above, this may be because depending on the number ofendpoints, either the representative relay link data rate or themulti-hop data rate may be the limiting data rate. More specifically, asthe number of slots used for the relay link increases (thus increasingthe representative relay data rate) the number of slots available forthe multi-hop access links decreases (thus decreasing the multi-hop datarate).

At step 445, a third number of slots are allocated to the single-hopaccess links. As with the second number of slots that were assigned tothe multi-hop access links, the third number of slots assigned to thesingle-hop access links may be based on the first number of slots thatwere assigned to the relay links and the total number of slots available(e.g., as depicted in FIG. 3A). More specifically, the third number ofslots may be determined by reducing the total number of slots availablewithin a particular downlink or uplink subframe by the first number ofslots assigned to the relay links.

At step 450 the third number of slots are divided among the single-hopaccess links. By using the link quality information associated with eachof the respective single-hop access links, it may be possible to ensurethat each single-hop access link is able to provide its endpoint with anapproximately equal single-hop data rate.

At step 455 the minimum data rate is determined by comparing thesingle-hop data rate with the effective multi-hop data rate. As may beapparent, increases in the effective multi-hop data rate could decreasethe single-hop data rate. Particular embodiments strive to maximize thisminimum data rate. In some situations it may be that minimum data rateis maximized when the effective multi-hop data rate is approximatelyequal to the single-hop data rate.

At decisional step 460 it is determined whether the minimum data ratehas reached its maximum value. This may be determined using a variety oftechniques. One such technique may involve initially allocating arelatively low number of slots to the relay links (thus providing arelatively low effective multi-hop data rate) at step 415. Then as theeffective multi-hop data rate increases, so too may the minimum datarate. The minimum data rate of each iteration (or a predetermined numberof the most recent iterations) may be stored and compared to the minimumdata rate of a previous iteration. Once the minimum data rate of thecurrent iteration is less than the minimum data rate of the previousiteration then the maximum value for the minimum data has been found(the minimum data rate of the previous iteration).

If the maximum value of the minimum data rate has not been determinedthen the method returns back to step 415 and a different first number ofslots is assigned to the relay link. As discussed above, when the firstnumber of slots are assigned to the relay link in this particularinstance, the number of slots will be assigned based on the first numberof slots that were assigned the first time step 415 was executed and howfar apart the resulting individual single-hop data rate and individualmulti-hop data rate differed. On the other hand, if the maximum value ofthe minimum data rate has been determined then the method continues tostep 465 where the slots are provisioned to the respective links. Morespecifically, the first number of slots are provisioned for the relaylinks, the second number of slots are provisioned to the multi-hopaccess links, and the third number of slots are provisioned to thesingle hop access links.

Once the slots have been provisioned, a downlink MAP is transmitted atstep 470. The downlink MAP may contain information indicative of theprovisioning of the slots. Thus, once it is received by the variousendpoints and relay stations, they are able to determine the appropriatesubchannel and time slots with which they are to send or receive data.These steps may be repeated before each frame begins so that thewireless resources are efficiently distributed and utilized even asdifferent endpoints enter into and exit out of the coverage area of aparticular base station or relay station.

As discussed above, the steps depicted in FIG. 4 may be repeated on aframe-by-frame basis. In other words, the downlink MAP that istransmitted may be continuously updated so that each time that adownlink MAP is transmitted for a new frame the slots are provisionedwithin the frame such that all endpoints, single hop access points andmulti-hop access points, receive approximately the same data rate.

Some of the steps illustrated in FIG. 4 may be combined, modified ordeleted where appropriate, and additional steps may also be added to theflowchart. Additionally, steps may be performed in any suitable orderwithout departing from the scope of particular embodiments. For example,in particular embodiments, slots may first be tentatively assigned tothe multi-hop access links and then assigned to the relay link.

Thus far several different embodiments and features have been presented.Particular embodiments may combine one or more of these featuresdepending on operational needs and/or component limitations. This mayallow for great adaptability of cell 200 to the needs of variousorganizations and users. For example, a particular embodiment may useseveral base stations to provide wireless access for a metropolitanarea, or a single base station may be used with several relay stationsto provide the necessary coverage and capacity. Furthermore, in someembodiments, relay stations 250 may have more or less radios. Someembodiments may include additional features.

While various implementations and features are discussed with respect tomultiple embodiments, it should be understood that such implementationsand features may be combined in various embodiments. For example,features and functionality discussed with respect to a particularfigure, such as FIG. 2, may be used in connection with features andfunctionality discussed with respect to another such figure, such asFIG. 1, according to operational needs or desires.

Although particular embodiments have been described in detail, it shouldbe understood that various other changes, substitutions, and alterationsmay be made hereto without departing from the spirit and scope of thepresent invention. For example, although an embodiment has beendescribed with reference to a number of elements included withincommunication system 100 such as endpoints, base stations and relaystations, these elements may be combined, rearranged or positioned inorder to accommodate particular routing architectures or needs. Inaddition, any of these elements may be provided as separate externalcomponents to communication system 100 or each other where appropriate.The present invention contemplates great flexibility in the arrangementof these elements as well as their internal components.

Numerous other changes, substitutions, variations, alterations andmodifications may be ascertained by those skilled in the art and it isintended that the present invention encompass all such changes,substitutions, variations, alterations and modifications as fallingwithin the spirit and scope of the appended claims.

1. A method for allocating resources in a wireless network, comprising:establishing one or more relay links between at least one base stationand one or more relay stations; establishing one or more single-hopaccess links between one or more endpoints and the base station;establishing one or more multi-hop access links between one or moremulti-hop endpoints and the relay stations; iteratively repeating thefollowing steps until a first, second and third number of slots areprovisioned: allocating the first number of slots to the relay links;dividing the first number of slots among the relay links; determining arepresentative relay data rate indicative of a data rate provided by oneof the relay links for a respective one of the multi-hop access links,the representative relay data rate based on the number of slots dividedto the respective relay link and the number of multi-hop access linksestablished with the respective relay station; allocating the secondnumber of slots to the multi-hop access links; dividing the secondnumber of slots among the multi-hop access links ensuring that eachmulti-hop access link comprises an approximately equal multi-hop datarate; determining the effective multi-hop data rate based on the minimumof the representative relay link data rate and the multi-hop data rate;allocating the third number of slots to the single-hop access links;dividing the third number of slots among the single-hop access linksensuring that each single-hop access link comprises an approximatelyequal single-hop data rate; determining a minimum data rate based on theminimum of the single-hop data rate and the effective multi-hop datarate; and upon determining that the minimum data rate has reached itsmaximum value, provisioning the first number of slots to the relaylinks, the second number of slots to the multi-hop access links, and thethird number of slots to the single-hop access links.
 2. The method ofclaim 1, wherein at least one of the relay stations comprises anon-transparent relay station.
 3. The method of claim 1, furthercomprising collecting link quality information associated with at leastone of at least the single-hop access links, multi-hop access links, orrelay links.
 4. The method of claim 3: wherein dividing the first numberof slots among the relay links comprises dividing the first number ofslots such that the number of slots divided to one of the relay links isproportional to the number of multi-hop access links established withthe respective relay station and inversely proportional to thelink-quality associated with the respective relay link; wherein therepresentative relay data rate is further based on the link qualityassociated with the respective relay link; further comprisingdetermining the multi-hop data rate for a multi-hop access link based onthe link quality associated with the multi-hop access link; and furthercomprising determining the single-hop data rate for a single-hop accesslink based on the link quality associated with the single-hop accesslink.
 5. The method of claim 1, wherein: allocating the second number ofslots to the multi-hop access links comprises: determining a totalnumber of slots available in a relay station sub-frame; and subtractingthe number of slots divided to one of the relay links from the totalnumber of slots available in a sub-frame; and allocating the thirdnumber of slots to the single-hop access links comprises: determining atotal number of slots available in a base station sub-frame; andsubtracting the first number of slots allocated to the relay link fromthe total number of slots available in the sub-frame.
 6. The method ofclaim 1, further comprising transmitting a downlink MAP for a frame, thedownlink MAP comprising information indicative of the provisioning forthe frame of the first number of slots, the second number of slots, andthe third number of slots.
 7. The method of claim 6, wherein the methodof claim 1 is repeated on a frame-by-frame basis before eachtransmission of a downlink MAP for a frame.
 8. The method of claim 1,wherein: establishing one or more relay links comprises establishing atleast one relay link between a first relay station and a second relaystation; and allocating the first number of slots comprises allocating afirst portion of the first number of slots to a relay link between thefirst relay station and the second relay station and a second portion ofthe first number of slots to a relay link between the base station andone of the first or second relay stations.
 9. An apparatus forallocating resources in a wireless network, comprising: an interfaceoperable to: establish one or more relay links between at least one basestation and one or more relay stations; establish one or more single-hopaccess links between one or more endpoints and the base station;establish one or more multi-hop access links between one or moremulti-hop endpoints and the relay stations; and a processor coupled tothe interface wherein, until a first, second and third number of slotsare provisioned, the processor is iteratively operable to: allocate thefirst number of slots to the relay links; divide the first number ofslots among the relay links; determine a representative relay data rateindicative of a data rate provided by one of the relay links for arespective one of the multi-hop access links, the representative relaydata rate based on the number of slots divided to the respective relaylink and the number of multi-hop access links established with therespective relay station; allocate the second number of slots to themulti-hop access links; divide the second number of slots among themulti-hop access links ensuring that each multi-hop access linkcomprises an approximately equal multi-hop data rate; determine theeffective multi-hop data rate based on the minimum of the representativerelay link data rate and the multi-hop data rate; allocate the thirdnumber of slots to the single-hop access links; divide the third numberof slots among the single-hop access links ensuring that each single-hopaccess link comprises an approximately equal single-hop data rate;determine a minimum data rate based on the minimum of the single-hopdata rate and the effective multi-hop data rate; and upon determiningthat the minimum data rate has reached its maximum value, provision thefirst number of slots to the relay links, the second number of slots tothe multi-hop access links, and the third number of slots to thesingle-hop access links.
 10. The apparatus of claim 9, wherein the atleast one relay station comprises at least one non-transparent relaystation.
 11. The apparatus of claim 9, wherein the interface is furtheroperable to collect link quality information associated with at leastone of at least the single-hop access links, multi-hop access links, orrelay links.
 12. The apparatus of claim 11, wherein: the processoroperable to divide the first number of slots among the relay links isfurther operable to divide the first number of slots such that thenumber of slots divided to one of the relay links is proportional to thenumber of multi-hop access links established with the respective relaystation and inversely proportional to the link-quality associated withthe respective relay link; the representative relay data rate is furtherbased on the link quality associated with the respective relay link; theprocessor is further operable to determine the multi-hop data rate for amulti-hop access link based on the link quality associated with themulti-hop access link; and the processor is further operable todetermine the single-hop data rate for a single-hop access link based onthe link quality associated with the single-hop access link.
 13. Theapparatus of claim 9, wherein: the processor operable to allocate thesecond number of slots to the multi-hop access links is further operableto: determine a total number of slots available in a relay stationsub-frame; and subtract the number of slots divided to one of the relaylinks from the total number of slots available in a sub-frame; and theprocessor operable to allocate the third number of slots to thesingle-hop access links is further operable to: determine a total numberof slots available in a base station sub-frame; and subtract the firstnumber of slots allocated to the relay link from the total number ofslots available in the sub-frame.
 14. The apparatus of claim 9, whereinthe interface is further operable to transmit a downlink MAP for aframe, the downlink MAP comprising information indicative of theprovisioning for the frame of the first number of slots, the secondnumber of slots, and the third number of slots.
 15. The apparatus ofclaim 14, wherein the processor operable to provision the first, secondand third number of slots is further operable to provision the first,second and third number of slots on a frame-by-frame basis before theinterface transmits each downlink MAP for a frame.
 16. The apparatus ofclaim 9, wherein: the interface operable to establish one or more relaylinks comprises an interface operable to establish at least one relaylink between a first relay station and a second relay station; and theprocessor operable to allocate the first number of slots is furtheroperable to allocate a first portion of the first number of slots to arelay link between the first relay station and the second relay stationand a second portion of the first number of slots to a relay linkbetween the base station and one of the first or second relay stations.17. Logic encoded on non-transitory computer readable media comprisingcode that, when executed by a processor, is operable to: establish oneor more relay links between at least one base station and one or morerelay stations; establish one or more single-hop access links betweenone or more endpoints and the base station; establish one or moremulti-hop access links between one or more multi-hop endpoints and therelay stations; iteratively repeating the following operations until afirst, second and third number of slots are provisioned: allocate thefirst number of slots to the relay links; divide the first number ofslots among the relay links; determine a representative relay data rateindicative of a data rate provided by one of the relay links for arespective one of the multi-hop access links, the representative relaydata rate based on the number of slots divided to the respective relaylink and the number of multi-hop access links established with therespective relay station; allocate the second number of slots to themulti-hop access links; divide the second number of slots among themulti-hop access links ensuring that each multi-hop access linkcomprises an approximately equal multi-hop data rate; determine theeffective multi-hop data rate based on the minimum of the representativerelay link data rate and the multi-hop data rate; allocate the thirdnumber of slots to the single-hop access links; divide the third numberof slots among the single-hop access links ensuring that each single-hopaccess link comprises an approximately equal single-hop data rate;determine a minimum data rate based on the minimum of the single-hopdata rate and the effective multi-hop data rate; and upon determiningthat the minimum data rate has reached its maximum value, provision thefirst number of slots to the relay links, the second number of slots tothe multi-hop access links, and the third number of slots to thesingle-hop access links.
 18. The computer readable media of claim 17,wherein the at least one relay station comprises at least onenon-transparent relay station.
 19. The computer readable media of claim17, wherein the code is further operable to collect link qualityinformation associated with at least one of at least the single-hopaccess links, multi-hop access links, or relay links.
 20. The computerreadable media of claim 17, wherein: the code operable to divide thefirst number of slots among the relay links is further operable todivide the first number of slots such that the number of slots dividedto one of the relay links is proportional to the number of multi-hopaccess links established with the respective relay station and inverselyproportional to the link-quality associated with the respective relaylink; the representative relay data rate is further based on the linkquality associated with the respective relay link; the code is furtheroperable to determine the multi-hop data rate for a multi-hop accesslink based on the link quality associated with the multi-hop accesslink; and the code is further operable to determine the single-hop datarate for a single-hop access link based on the link quality associatedwith the single-hop access link.
 21. The computer readable media ofclaim 17, wherein: the code operable to allocate the second number ofslots to the multi-hop access links is further operable to: determine atotal number of slots available in a relay station sub-frame; andsubtract the number of slots divided to one of the relay links from thetotal number of slots available in a sub-frame; and the code operable toallocate the third number of slots to the single-hop access links isfurther operable to: determine a total number of slots available in abase station sub-frame; and subtract the first number of slots allocatedto the relay link from the total number of slots available in thesub-frame.
 22. The computer readable media of claim 17, wherein the codeis further operable to transmit a downlink MAP for a frame, the downlinkMAP comprising information indicative of the provisioning for the frameof the first number of slots, the second number of slots, and the thirdnumber of slots.
 23. The computer readable media of claim 22, whereinthe code is further operable to repeat the operations of claim 15 on aframe-by-frame basis before each transmission of a downlink MAP for aframe.
 24. The computer readable media of claim 17, wherein the codeoperable to: establish one or more relay links is further operable toestablish at least one relay link between a first relay station and asecond relay station; and allocate the first number of slots is furtheroperable to allocate a first portion of the first number of slots to arelay link between the first relay station and the second relay stationand a second portion of the first number of slots to a relay linkbetween the base station and one of the first or second relay stations.